Institut Pasteur, 25 Rue du Docteur Roux, 75015 Paris, France.
Res Microbiol. 2011 Jan;162(1):77-91. doi: 10.1016/j.resmic.2010.10.005. Epub 2010 Oct 27.
I discuss here the possibility that Eukarya originated from the engulfment of a thaumarchaeon by a PCV (Planctomycetes, Verrucomicrobia, Chlamydiae) bacterium, followed by invasions of NCLDV and retroviruses. The thaumarchaeon provided both informational and operational proteins (actins, ESCRT proteins), including some essential proteins absent in other archaeal phyla (Topo IB), whereas the PVC bacterium provided phospholipids, tubulin and the membrane coat proteins required for the formation of the nucleus. Viral invasions introduced many proteins that are specific to modern Eukarya and produced an arms race that favoured the evolution of Eukarya toward increasing complexity. This scenario is the best possible fusion hypothesis that can be presently proposed. However, it still requires several ad hoc assumptions to explain the origin of the nucleus and the distribution pattern of archaeal and bacterial traits in modern Eukarya. Furthermore, it still fails to explain convincingly the origin of eukaryal viruses and the existence of three distinct lineages of ribosomes. I conclude that Eukarya and their viruses more probably evolved from a specific lineage, according to the three domains scenario originally proposed by Carl Woese.
我在这里讨论了真核生物可能起源于被 PCV（盘状螺旋体门、疣微菌门、黏体门）细菌吞噬的古菌，随后被 NCLDV 和逆转录病毒入侵。古菌提供了信息和操作蛋白（肌动蛋白、ESCRT 蛋白），包括一些其他古菌门中缺失的必需蛋白（拓扑异构酶 IB），而 PVC 细菌则提供了磷脂、微管蛋白和形成核所需的膜壳蛋白。病毒入侵引入了许多专门针对现代真核生物的蛋白质，并引发了一场军备竞赛，有利于真核生物向更高的复杂性进化。这是目前可以提出的最佳融合假说。然而，它仍然需要一些特定的假设来解释细胞核的起源和现代真核生物中细菌和古菌特征的分布模式。此外，它仍然无法令人信服地解释真核生物病毒的起源以及三种不同的核糖体谱系的存在。我得出的结论是，根据卡尔·沃斯最初提出的三域假说，真核生物及其病毒更可能从一个特定的谱系进化而来。
